Method and apparatus for molding concrete pipe



C. B. BREEDLOVE sept. 16, 1941.

METHOD AND APPARATUS FOR MOLDNG CONCRETE PIPE 2 Sheets-Sheet 1 Filed May 26, 1958 Snventor v l Gttmegs (ar/@S greed/Ove,

.N @HN Nm NN QN Y Sept 16, 1941- c. B. BREr-:DLovE 2,256,235

METHOD AND A?PARATUS FOR MOLDING CONCRETE PIPE Filed May 26, 1958 2 Sheets-Sheet 2 :Snoentor E /f//A' 7 Gttornegs Patented Sept. 16, 1941 METHOD AND APPARATUS Fon MoLDING CONCRETE PIPE 'Charles B. Breedlove, Detroit, Mich. Application May 26, 1938, Serial No. 210,240

3 Claims.

I'his invention relates in general to a method of and apparatus for forming concrete piping, and it is particularly related to the formation of monolithic or seamless piping to be used in sewer and other work employing concrete piping.

One of the main objects of this invention is to provide an improved concrete pipe-forming process whereby the piping is formed and laid simultaneously without the otherwise necessary handling thereof.

Another object of the invention is to improve the art of forming concrete piping so that the formation process is continuous from start to nish throughout the entire length of the pipe, the resulting pipe being monolithic and seamless, and the process of the forming thereof at the same time accomplishing the laying thereof.

Another object of the invention is to employ the same pressure which is used for introducing the Wet concrete into the forms for the piping to remove said forms from those portions of piping which have initially set, said pressure in moving said forms at the same time increasing the density of the concrete in said piping.

Another object herein is to provide improved apparatus for use in the above novel process for the accomplishment of the above objects.

Other objects and advantages will become readily apparent from a reference to the following specification taken in conjunction with the accompanying drawings, of which there are .two (2) sheets and in which:

Figure 1 shows they pipe forming apparatus in position for accomplishing the first step in the continuous process of simultaneously forming and laying the formed pipe;

Fig. 2 shows the apparatus and pipe during an advanced step of the process;

Fig. 3 shows the apparatus and pipe at the final stage of forming and laying of the latter, and

Figs. 4 and 5 are transverse sections through the pipe and apparatus in cases where the process is to be performed on open-cut or tunnel Work, respectively.

There is shown in Figs. 1 through 4 a pre-cut trench I with a form I2 disposed therein and solely supported thereby. Form I2 is shown in cylindrical cross section, but such specic showing is for the purpose of illustration only. Internally disposed within the form I2 is an inner form or pilot, generally indicated at I4, the form I4 being held at one end in proper spaced relation to form I2 by means of an annular cap 55V member I which is secured thereat .to both of said forms, the proper spacing between said forms and along their lengths as the concrete is forced between the forms being attained by the use of a spacing member AI8 which is slidable between the forms I2 and I4 in close fitting relation thereto and ahead of the concrete by the pressure of the concrete.

The inner form or pilot I4 is preferably made up of a plurality of separately attachable and removable sections 20, joined together by bolts or `other means, and made individual for the purpose of acquiring the proper length of the assembled form I4. It is to be noted that the length of form I4 is shown as approximately double that of form I2, the purpose of which to be explained later. Any conventional type of supporting means 22 for the freer end of form I4 may be used, its use being optional but many times preferable, especially for inner forms of great length.

The outer form I2 is provided near its forward end with an inlet 24 into which concrete 25 is forced under high pressure by the pumping apparatus, generally indicated at 28. Apparatus 28 can be of any known type as long as it is capable of producing pressures high enough lfor the accomplishment of the desired results. In open-cut Work, such as in Figs. 1 through 4, apparatus 2K8 may either be `supporti-:d on the form I2 as shown, or it may be supported on the bank Ill and in communication with inlet 24 by means of a flexible supply conduit (not shown) In tunnel work, such as in Fig. 5, apparatus I28, similar to apparatus 28, is mounted on the inside of the inner form II4, similar to inner form I4 except for the provision in the form I'I4 of the inlet |24, the tunnel and outer form in Fig. 5 being represented, respectively, by the numerals Ill! and II 2.

Since the invention contemplates the application of end thrust at the initially-set end of the concrete, namely, at the free end of the outer form I2, such as is shown in Fig. 2, so that subfsequent pressure on Ithe concrete applied at the inlet 24 will cause the forms I2 and I4 to move away from that end of the concrete lwhich has initially set, such as is shown in Fig. 3, the trench I0 is presumed to have been cut out so as to accommodate the extra sections 2li of inner form I4. The end of the trench Ill, indicated at 30, will then serve as an abutment for the jacks or other thrust reacting members, generally and diagrammatically indicated at 32. It is necessary to have the trench IIllonger than the outer form I2, but it need only be long enough to ac'- commodate a single extra section 29, any that need be added later as the inner form is drawn away from the set end of the pipe can be added as needed. Also, instead of the jacks 32 there can be employed a system of vertical piling (not shown), said piling being driven into the ground up against the end of the spacing member I8 and the circumference of the inner form I4 so that the thrust of form I4 will be properly taken up by said piling. Other thrust reacting means may be employed and the Vinvention contemplates that same are available for use.

When Ithe apparatus, including the outer and inner forms I2 and I4, the bulk-head and spacing members I6 and I8, and the pumping apparatus 28, have been assembled as shown in Fig. 1, concrete 26 is forced under high pressure through the inlet V24. The longitudinal speed of travel of the forms I2 and I4 governs the lengths thereof necessary toA insure proper hardening of the concrete in the piping formed thereby, and it also governs the amount of hydraulic pressure required; in other words, said necessary form length is directly proportional to said chosen form speed, and said required pressure is also directly proportional to said chosen form speed. The concrete entering the annular space between the forms I2 and I4 is forced through and along this space, as Shown in Fig. 2, until it reachesthe free end of the outer form I2, the spacing mein--` ber I8 being movable vahead of the concrete and properly'spacing during its -travel the forms I2 and I4 one from the other, and said forms remaining stationary during this step of the process.

When or before the concrete reaches the free end of the form I2, the jacks 32 or other` suitable thrust reacting means are placed in position, as shownin Fig. 2, the thrust reaction thus set up causing a pressure to be built up by the pumping apparatus suicient to move the two forms I2 and I4 as a unit away from the thrust supported end'of the concrete pipe. The movement of the two forms I2 and I4 by the pressure of the incoming concrete continues until the pipe is formed'in desired length, said leng-th comprising the portions lying without and withinV the two forms I2 and I4. The supply of concrete is then shut oli, but the motion of the two forms is continued in the same direction and at the same rate of speed as before by the pumping apparatus, jacks or other means, so that the pipe throughout its entire length will have been conned between the two forms for a uniform time.

From the above discussion and description it `willV be seen that the pipe forming process provides a uniformly set pipe when it, as in Fig. 3, is freed by both forms I2 and I4. The two forms f support the concrete during the length of time it'takes the incoming concrete to reach the end of the outer form, and the inner form, being substantially double the length of the'outer form, continues to support thepipe internally for the additional lengthV of l time it takes the freev end of the inner form to traverse theportion of the pipe uncoveredv by the outer form. The pressure exerted on the concrete against the thrust reaction of the jacks 32 increases the density of the concrete. And, the formed pipe is made seamless and monolithic, the'process is Vcontinuous from start to iinish, and the pipe is laid as it is formed, al1 because of the inherent nature of this novel process. Increasing the density of the concrete enables the thickness of the pipe in any case to be materially cut down.

Concrete of normal consistency to be used for sewer work of normal dimensions becomes initially set after approximately iive hours. Therefore, the inner form is of such a length as to have internally supported each particle of concrete being leit unsupported thereby for said live hours. Practice has proved that the concrete need be externally supported for a period of approximately between two and three hours, and

Y the length of the outer form is, therefore, made accordingly.

The disclosure in Fig. 5 shows the adaptation 'ofthe described novel method of and apparatus4 forV forming and laying piping to tunnel work,

as distinguished from open-cut work, the only differences being that the wet concrete is introduced into the forms through the inner form ratherthan through the outer lform, the outer form is made shorter than the open-cut outer form so that the concrete will leave the outer form while still not initially'set and of such consistency as to ll the'void between the earthen tunnelV wall and the inner form, the inner form is made shorter than the open-cut inner form because the form speed in tunnel work is much slower than the form speed in open-cut work for the same size pipe, and the pumping apparatus is carried by the inner form rather thanby the outer form'or by the bank, asin open-cut work. This method and apparatus used in tunnel work is an important time saver, there being no stoppage during the forming and laying process, as in brick tunnelling, and there being no need for relining the formed tunnel, as in block tunnelling with shields. In brick tunnelling, the sand hogs dig while the brick masons must idly wait, and viceversa; in the above novel method, the sand hogs dig while the concrete pipe is being formed and laid. In block tunnelling with'shields, the entire inner wall of the tunnel must be relined with a thick facing in order to'seal the block limit the scope of the inventive idea. V'Ihe right isreserved to make such changes Ain the-specification as will come within the purview of the attached claims. I

What I claim is: Y Y

l. The method of simultaneously forming and laying concrete pipe'for tunnel purposes which comprises, concentrically positioning a 'pair of annularv forms so that their common axis is substantially coincident with the axis of the desired pipe and the annulus between which forms Vis cross sectionally 4dimensioned similarly'as the pipe and has a closed end, introducing Wet con` crete under pressure into the annulus from within the inner form along a continuously unrestricted path of travel so that the concrete is free to move longitudinally through the annulus toward the end thereofV opposite said closed end exclusively under the inuence of said pressure,` and terminating thev travel of the concrete toward said opposite end when the concrete thereat'is in a position corresponding to the position se;

.lected to be occupied by one end oi' the pipe, whereupon the reaction set up by said closed end and the immobile concrete when concrete introduction and pressure application are continued eifectuates movement of the forms away from said one end of the pipe toward the position selected for the other end of the pipe.

2. In an apparatus for simultaneously forming and laying concrete pipe for tunnel purposes and comprising, a pair of concentrically disposed forms defining an elongated annulus having a cross section similar to that of the pipe to be formed and an axis capable of being arranged substantially coincident with the axis desired for the pipe, a closure member carried by said forms over the head end of said annulus, means providing a source of wet concrete, means providing a source of pressure applicable to said vconcrete for bodily moving the latter, and concrete flow inlet means formed in and carried by the inner form of said pair and providing from within said inner form an unrestricted communication between said annulus and said moving conrete so that concrete entering said annulus under the iniiuence of said pressure is thereafter conveyed for a predetermined period of form immobility through said rannulus toward. the end thereof opposite said closure carrying end exclusively responsive to said pressure and thereafter against said closure member to protract said forms relatively to said concrete.

3. In an apparatus for simultaneously forming and laying concrete pipe for tunnel purposes and comprising, a pair of concentrically disposed forms defining an elongated annulus having a cross section similar to that of the pipe to be formed and an axis capable of being arranged substantially coincident with the axis desired for the pipe, a closure member carried by said forms over the head end of said annulus, means providing a source of wet concrete, means `carried within the inner form of said pair and providing a source of pressure in active communication with said concrete for bodily moving the latter, and concrete flow inlet means formed in and carried by said inner form and providing from within said inner form an unrestricted communication between said annulus and said moving concrete so that concrete entering said annulus under the influence of said pressure is thereafter conveyed for a predetermined period of form immobility through said annulus toward the end thereof opposite said closure carrying end exclusively responsive to said pressure and `thereafter against said closure member to protract said forms relatively to said concrete.

CHARLES B. BREEDLOVE. 

